Communicating control information in mobile communication system

1. A method for a mobile terminal to transmit scheduling information to a network in a mobile communication system, the method comprising: receiving, during a transmission to the network of a first protocol data unit (PDU) of a medium access control (MAC) layer comprising first data received from an upper layer that is higher than the MAC layer, second data from the upper layer to be transmitted to the network with a higher priority than the first data, wherein the transmission of the first PDU is performed using a first hybrid automatic repeat request (HARQ) process associated with a first timing point on which the first PDU is transmitted; triggering scheduling information providing the network with information regarding an amount of data available for transmission in a buffer of the mobile terminal upon receiving the second data from the upper layer; generating a second PDU of the MAC layer comprising the triggered scheduling information; and transmitting the second PDU to the network using a second HARQ process associated with a second timing point on which the second PDU is transmitted, wherein the second timing point is different from the first timing point, and wherein the second timing point occurs before a third timing point on which feedback information regarding the first PDU is received, and wherein the second HARQ process allows the transmission of the second PDU before the feedback information regarding the first PDU is received.

2. The method of claim 1 , wherein the priority is related to a logical channel through which data is delivered.

3. The method of claim 1 , wherein the mobile terminal further triggers scheduling information requesting uplink resources for transmitting the second data to the network when the mobile terminal does not have the uplink resources upon receiving the second data from the upper layer.

4. The method of claim 1 , wherein the second PDU further comprises data to be transmitted to the network with the triggered scheduling information.

5. A mobile terminal for transmitting scheduling information to a network in a mobile communication system, the mobile terminal comprising: a processor for generating a first protocol data unit (PDU) of a medium access control layer (MAC layer) comprising first data received from an upper layer that is higher than the MAC layer, and generating a second PDU of the MAC layer comprising triggered scheduling information providing the network with information regarding an amount of data available for transmission in a buffer of the mobile terminal; and a transmitter controlled by the processor to transmit to the network the first PDU using a first hybrid automatic repeat request (HARQ) process associated with a first timing point on which the first PDU is transmitted, and the second PDU using a second HARQ process associated with a second timing point on which the second PDU is transmitted, wherein the processor is configured to trigger the scheduling information upon receiving, during a transmission of the first PDU using the first HARQ process, second data from the upper layer to be transmitted to the network with a higher priority than the first data, wherein the second HARQ process allows the transmission of the second PDU before feedback information regarding the first PDU is received, and wherein the second timing point is different from the first timing point, and wherein the second timing point occurs before a third timing point on which the feedback information regarding the first PDU is received.

6. The mobile terminal of claim 5 , wherein the priority is related to a logical channel through which data is delivered.

7. The mobile terminal of claim 5 , wherein the processor is further configured to trigger scheduling information requesting uplink resources for transmitting the second data to the network when the mobile terminal does not have the uplink resources upon receiving the second data from the upper layer.

8. The mobile terminal of claim 5 , wherein the second PDU further comprises data to be transmitted to the network with the triggered scheduling information.